Known examples of the high-performance rare earth magnet include an Sm—Co-based magnet, an Nd—Fe—B-based magnet, and a similar magnet. Fe and Co in such magnets contribute to an increase in saturation magnetization. These magnets contain a rare earth element such as Nd and Sm. Derived of a behavior of 4f electron in the rare earth elements at a crystal field, the rare earth elements bring about large magnetic anisotropy. This creates a large coercive force, thereby providing a high-performance magnet.
Such high-performance magnet is mainly used for electrical devices such as a motor, a speaker, and a measuring instrument. In recent years, requests on downsizing, weight reduction, and low power consumption have been increased on various electrical devices. In response to the requests, there is a demand for a permanent magnet with higher performance that has an improved maximum magnetic energy product (BHmax) of the permanent magnet. In recent years, a variable magnetic flux motor has been proposed. This contributes to an improvement in efficiency of a motor.
Since the Sm—Co-based magnet features high Curie temperature, the Sm—Co-based magnet can achieve good motor property at high temperature. However, a higher coercive force, higher magnetization, and an improvement in a squareness ratio have been desired. It is presumed that high concentration of Fe is effective to increase the magnetization of the Sm—Co-based magnet. However, with the conventional manufacturing method, high concentration of Fe deteriorates the squareness ratio. In order to provide a high-performance magnet for motor, therefore, a technique that achieves the good squareness ratio while improving the magnetization with the high Fe concentration composition is necessary.